I’m starting to play around with ufw (Ucomplicated Firewall), a firewall for Linux.

It’s command line based, but simple enough.

I’ll update this post as I play along.

Enable/disable ufw

sudo ufw enable
sudo ufw disable 

Default policy

  • mostly open ports
sudo ufw default allow
  • mostly closed ports
sudo ufw default deny 

Allow/deny services syntax

sudo ufw allow|deny <service> 

Add rules syntax

sudo ufw allow|deny [proto <protocol>] [from <address>  [port <port>]] [to <address> [port <port>]] 

Delete rules syntax

sudo ufw delete <rule type> from <ip address> to any port <port number> 

Firewall status

sudo ufw status 
Firewall loaded
To                         Action  From
--                         ------  ----
24800:tcp                  ALLOW   100.000.1.1

Examples

sudo ufw allow proto tcp from 100.000.1.1 to any port 24800
sudo ufw delete allow proto tcp from 100.000.1.1 to any port 24800
sudo ufw allow ssh
sudo ufw delete allow ssh